The present invention relates to a cooling system for an electric vehicle inverter system and, more particularly, to a cooling system for an electric vehicle inverter system which is capable of effectively cooling the inverter in an inverter system.
It has been known to use a cooling system of the water cooling type instead of the using a cooling system of air cooling type in order to cool an electric power converting apparatus (inverter system) mounted on an electric vehicle, as described in, for example, Japanese Patent Application Laid-Open No. 4-275492 (1992).
In a cooling system of this type, the cooling of each of a number of electric power converting units provided in an electric vehicle is performed by a single cooling system formed as a unit, and cooling is classified into two patterns, a battery charging pattern and a running pattern, to selectively cool a battery charger and a DC/DC converter operating during battery charging, as well as an inverter and a DC/DC converter operating during running.
For cooling an IGBT (insulated gate bipolar transistor) and the like, it has been common to use a heat sink of the air cooling type, as described in, for example, Japanese Patent Application Laid-Open No. 47-31317 (1972).
According to the former publication, an excellent cooling system of the water cooling type is provided since cooling is performed with forced convection and the main part of the inverter is locally and effectively cooled. However, there is a disadvantage in that it is difficult to directly employ the system for commercial use in an electric vehicle because of insufficient capacity of the available space and a weight bearing problem.
In the latter system of the air cooling type, there are many air heat sinks to cool heat generating bodies, such as IGBT's, and a duct, a blower and the like are required to conduct the cooling air to the fins of the heat sinks. The units are large in size and require a large room when these units are mounted on a vehicle, which decreases its during efficiency. In addition to this, since a large air flow rate and high outlet pressure are required, the blower makes a large noise.